Gas meters are measurement devices to record the amount of gas passed through per unit time. The area of use of gas meters is not restricted to just domestic or industrial gas supply, but also exact amount determination in laboratory investigations. For special applications gas meters are equipped with interfaces or potential-free contacts, which permits remote query of meter states or further processing of the measured consumption.
A modular gas meter is already known for this purpose from EP 0843287 B1, which has a base meter unit, an additional component, a gas closure valve, a gas flow meter arrangement and a first communication interface to transmit control data from or to the valve control system. The base meter unit is then configured so that it can be combined operationally with the additional component in order to expand the functions of the meter in so doing. The additional components include a component control system, set up so that it can control the functionality. The component control system has a second communication interface, via which communication signals are sent to control the base meter unit. The characteristic of this invention is that the additional component is arranged so that it calculates a closure-volume index which is sent to the base meter unit, which compares this value with the actual volume index volume and is arranged so that it trips the closure valve for interruption of gas supply as soon as the current volume index value reaches or surpasses the closure volume index value.
DE 101 293 00 A1 discloses a mass flow meter-detector, especially gas meter, as well as a method for data exchange. A gas meter includes a mass flow meter-detector, a control and a display. The gas meter can also be equipped with a card reader and a valve. The mass flow-detector is based on a sensor element, which is integrated on a semiconductor component together with a digital and analog evaluation. Since the mass flow rate and not the flow rate or volume of the consumed gas is measured, a value independent of pressure is obtained, which is essentially determined by the calorific value of the gas.
A gas meter and a method for determination of a consumed amount of gas are known from U.S. Pat. No. 6,470,741. The gas meter is characterized by a mass flow rate detector to measure the mass flow rate of a gas flowing through a main channel and also with means for integration of the mass flow rate over time.
A connection device for gas meters can be deduced from DE 4007279 C2. The connection device includes a shut-off valve, pressure regulator and an overpressure safety valve, which are connected in a feed line. A connection piece with three connectors is connected to the feed line, a first connector of which is provided for connection of the gas meter, a second for connection of the consumer and the third connection is provided with a gas shut-off valve, whose shut-off element is adjustable by means of a rotatable pin in a closed and open position. A characteristic of this invention is that the rotary pin is provided with a through hole, which runs axially in the rotary pin and is connected gastight to a removable closure or a closure being opened.
A device to secure against unauthorized gas removal from pressurized gas lines is also known from DE 38006261 C2, from which the gas meter is disassembled. A characteristic for this invention is that a plug inserted into the gas line is provided with at least one rubber hollow cylinder or ring, which is sealed against the walls of the gas line, imparts a fixed seat to the plug and is configured so that it can only be removed with a special tool.
A dry gas meter is known from U.S. Pat. No. 3,587,315, which includes a number of measurement chambers and a single valve. This valve always prevents direct gas flow between an inlet and an outlet. A working cycle is run, during which each of the individual chambers of the gas meter is connected for a specified time via a passage opening specially assigned to it to an inlet and for additional time to an outlet and for the remaining time of the work cycle is sealed relative to the inlet, the outlet and all other chamber passages. A characteristic of this invention is that the valve has a valve slide, which simultaneously rotates and moves in translational fashion in the same plane to execute an oscillating movement.
The gas meters known from the prior art have the drawback that, on the one hand, the shut-off valves present as separate components are connected in front of the gas meter and can therefore also be operated by unauthorized third parties. In the past this has often meant that consumers have replaced line sections, bypassing the gas meter and therefore enjoyed free and therefore illegal gas supply. In solutions of gas meters with integrated shut-off valves, on the hand, high pressure losses are registered, since these shut-off valves are functionally optimized but are not optimized in terms of flow.